Essential for life, sunshine can be found throughout the world. Not all locations on Earth's surface enjoy the same amount of sunlight, however.

How Sunlight Hours Are Measured

Daily and yearly average sunlight is measured according to a specific metric laid out by the World Meteorological Association. "Sunshine hours" are measured by sensors and count toward the total when the direct solar irradiance surpasses a specific threshold of at least 120 watts per square meter. This is different from visible sunlight that one might observe at sunrise and sunset, as this sunlight does not reach this minimum threshold. Cloudy conditions, shadows, fog and geographic features can limit sunshine hours, even in areas that receive plenty of visible sunlight.

Sunniest Places on Earth

The American Southwest and northeastern Africa are the two sunniest regions of the world, with the U.S. city of Yuma, Arizona, taking the crown as the sunniest place on Earth. Yuma, located where the state borders both California and Mexico, receives more than 4,000 sunlight hours per year and averages 11 sunny hours per day over the course of the year. Following closely behind Yuma is another U.S. city -- Phoenix -- which receives an average of 3,872 sunlight hours a year. The third sunniest spot on Earth is Aswan, Egypt, which has an average of 3,863 sunlight hours every year and averages 10.6 sunny hours per day.

Sunniest Months

Yuma gets consistent sunshine throughout the year, which accounts for its placement as the sunniest place on Earth. There are some places, however, that have sunnier months than Yuma does. The human settlement that gets the most sunshine in a particular month is northern Canada's Eureka during the month of May, where the daily sunlight averages 16.5 hours. This Arctic outpost claims this this spot due its bright sunshine (faint sunlight is not included, as it does not reach the sunlight threshold set forth by the World Meteorological Association) in an area where the sun does not set during summer.

Midnight Sun

While some places get a tremendous amount of sunlight over the course of a year, others get their sunlight all at once. Places north of the Arctic circle and south of the Antarctic circle have days where the sun never sets. This phenomenon is due to how the planet is tilted 23 degrees on its axis. During summer months -- up to six months per year -- countries above the Arctic circle see constant sunlight and the "midnight sun."